Given the chemical reaction fe3o4 + h2 ⟶ fe + h2o, identify the coefficient of h2o in the balanced equation.

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

8) warming your hands by a fire is an example if which heat transfer? a. conduction b. convection c. radiation d. none of these

27 drag each label to the correct location on the image. a particular exosolar system has five planets in total: a, b, c, d, and e. the table lists the orbital periods of these planets in days. planet orbital period (days) a 600 b 80 c 1,000 d 500 e 100 move each planet to its orbit in the system.